This invention relates to improvements in assembling continuing track rail sections with joint bars held together by nut and bolt holding members and, in particular, to a method and apparatus for preventing loosening rotation of the nut after they have been drawn down and tightened on the bolt members.
It is well known in the railroad industry to join continuing sections of track rail with splice bars and joint bars held in place by means of nut and bolt fasteners. Track joints assembled in this manner are economical to construct but suffer from the long standing problem that, as heavy equipment passes over the joints, strong vibrational forces are set up that causes loosening of the nuts to occur.
In a typical joint assembly, abutting ends of rail sections are sandwiched between a pair of elongated splice or joint bars, the bars extending along each rail section for about eighteen inches. Each of the bars has a series of bolt holes spaced about six inches apart which are accurately aligned with corresponding bolt holes in the fish or vertical portion of the rail sections. Conventionally, alternate ones of the bolt holes in the bars are crosswise elongated with flat portions that mate with flat shoulders on the bolt heads to prevent rotation of the bolt after it is inserted through the bar/rail assembly. Thus, the six bolts are usually inserted alternately from opposite sides of the assembly. After insertion of the bolts, with or without elongated backer plates depending on whether electrically insulated bars are used, a lock washer is inserted over the projecting threaded portion of each bolt. A nut is then threaded onto each bolt and drawn down and tightened to a desired torque value established and well known in the railroad industry.
Over long periods of time, repeated passage of heavy rail equipment of the joint sets up high vibrational forces which can cause the nuts to loosen on the bolts despite the action of the heavy duty lockwashers. When this occurs, the splice or joint bars can loosen, vibrate, and become broken setting up a dangerous track condition which can result in train derailment.
It is therefore an object of the present invention to provide improved track rail joint assemblies which obviate the disadvantages and problems of conventional assemblies.
It is a further object of the present invention to provide method and apparatus for restraining loosening rotation of nuts on track rail joint assemblies that is convenient and economical to use.
It is still further an object of the invention to provide method and apparatus that improves the reliability and safety of track joint assemblies.